wow, it's obvious a lot of work went into this script and the 'YouTube metadata search engine'... it should become popular if people understand its usefulness.
In my case, it yielded useful r###lts, as it turns out most of the missing videos in my playlist were either 'Joe Rogan podcasts' or 'interesting Reddit topics' videos... I'm able to recover all the podcast episodes free on Spotify, and all the Reddit source posts on its forums... cheers